1. Field of the Invention
The present invention relates to an outboard engine system comprising a 4-cycle engine including an engine block, a cylinder head coupled to the engine block and having an intake port in one side thereof, a carburetor including a carburetor body disposed on one side of the engine block adjacent the intake port to define an intake passageway, and a bypass-type starting device mounted to the carburetor body, and an intake pipe means which connects the intake passageway and the intake port to each other, at least an upper half of the engine including the carburetor being covered with an engine cover.
2. Description of the Related Art
Such an outboard engine system is conventionally known, for example, from Japanese Patent Application Laid-open No.4-252870.
In the above known system, the bypass-type starting device is mounted to the carburetor body disposed on one side of the engine block, on the opposite side from the engine block, and is disposed to protrude outwards from the carburetor body. For this reason, there is a possibility that the size of the engine cover may be increased in order to avoid the interference with the bypass-type starting device.
The present invention has been accomplished in view of the above circumstances, and an object of the present invention is to provide an outboard engine system, wherein the increase in size of the engine cover can be avoided.
To achieve the above object, according to a first aspect and feature of the present invention, there is provided an outboard engine system comprising a 4-cycle engine including an engine block in which a vertically extending crankshaft is rotatably carried, a cylinder head coupled to the engine block and having an intake port in one side thereof, a carburetor including a carburetor body disposed on one side of the engine block adjacent the intake port to define an intake passageway, and a bypass-type starting device mounted to the carburetor body, and an intake pipe means which connects the intake passageway and the intake port to each other, at least an upper half of the engine including the carburetor being covered with an engine cover, wherein the bypass-type starting device of the carburetor is mounted to the carburetor body between the intake passageway and the engine block.
With such arrangement of the first feature, the bypass-type starting device of the carburetor is mounted to the carburetor body between the intake passageway and the engine block. Therefore, the bypass-type starting device does not protrude outwards from the carburetor body and thus, it is possible to avoid the increase in size of the engine cover in order to avoid the interference with the bypass-type starting device.
According to a second aspect and feature of the present invention, in addition to the first feature, the carburetor is formed into a variable Venturi type. With such arrangement, the Venturi area of the intake passageway can be varied depending on an operational state of the engine, thereby enhancing the accuracy of an air-fuel ratio and providing a reduction in fuel consumption and an enhancement in nature of an exhaust gas.
According to a third aspect and feature of the present invention, in addition to the first or second feature, the outboard engine system further includes an intake silencer box connected to an upstream end of the carburetor, the carburetor and the intake silencer box being disposed on one side of the engine block with a cylinder axis thereof extending in a longitudinal direction of the outboard engine system, the intake silencer box being provided inside with a first air passage connected at a downstream end thereof to the carburetor for guiding air in a direction substantially along the cylinder axis, and a second air passage in which a direction of flowing of the air at least in a downstream end thereof is substantially perpendicular to a direction of flowing of the air in the first air passage, and an upstream end thereof opens to the outside, and a cleaner element disposed in a plane substantially parallel to the direction of flowing of the air in the first air passage and interposed between an upstream end of the first air passage and the downstream end of the second air passage, the cleaner element being accommodated and fixed in the intake silencer box.
With such arrangement of the third feature, the cleaner element is accommodated and fixed in the intake silencer box, so that the air is purified in the cleaner element while flowing from the second air passage to the first air passage. Moreover, the first air passage permits the air to flow therethrough in the direction substantially along the cylinder axis of the engine block, i.e., in the substantially longitudinal direction of the outboard engine system, and the cleaner element is disposed on the plane substantially parallel to the direction of flowing of the air in the first air passage. Therefore, the size of the intake silencer box does not increase in the lateral direction of the outboard engine system due to the disposition of the cleaner element, and it is possible for the intake device to have an air purifying function, while avoiding the increase in size of the intake device.
According to a fourth aspect and feature of the present invention, in addition to the third feature, the direction of flowing of the air in the downstream end of the second air passage is set in the lateral direction of the outboard engine system, and the second air passage is disposed between the engine block and the cleaner element disposed in a plane extending along the substantially vertical direction of the outboard engine system. With such arrangement, an opening at the upstream end of the intake silencer box can be disposed at a location where the opening is covered with the intake silencer box itself, and water entering the cover covering the engine can be prevented to the utmost from being drawn into the intake device.
The above and other objects, features and advantages of the invention will become apparent from the following description of the preferred embodiment taken in conjunction with the accompanying drawings.